Prediction of enthalpy and entropy interaction coefficients by the “central atoms” theory

Abstract A new model is developed which expresses the thennodynamic properties of a solution as a result of changes in the configuration of the nearest neighbor shell. Its simplest form introduces the quasiregular solution, which retains the simplicity of the regular solution while predicting more successfully the excess entropy; the equation of the model for the binary A–B solution is: G E = ZX A X B ω(1 − T gt ) Several relations are predicted between zeroth and first order free energy enthalpy and entropy interaction coefficients and are shown to be in fair qualitative agreement with experimental observations in the literature. In particular they satisfactorily explain discrepancies in the results of the use of the regular solution or quasi-chemical theory. A basis for the evaluation of excess entropy from free energy or enthalpy data is also devised and shown to be in fair agreement with observed empirical correlations.